Toyota's interest may not be in Level-5 autonomous taxis. They have a history of striving to fully understand every part of their supply chain; this could be a play at developing advanced in-house driver assists.

As an example, I was surprised to learn that Toyota designed their own ECU chips rather than buying off-the-shelf automotive grade MCUs until 2019, when they spun that business off to a subsidiary[1]. They really take vertical integration seriously.

[1]: https://www.reuters.com/article/us-japan-fukushima-anniversa...